0028248: [Regression] HLR Algo result is retrieved from the last added shape only

Description

Found in OCCT 7.1.0 as a regression to 7.0.0.

If multiple shapes are added to HLRBRep_Algo, the extract comound shape (via HLRBRep_HLRToShape) does contain edges from the last added shape only. If the first shape is given as reference shape to the *Compound function, the result is empty. If the shapes are added in reversed order, the result will also change to the then last shape. The hidden line removal itself seems to be correct.

This error can be fixed with the applied patch. The change is extremely small, so I hope I can contribute this way. The result is still different to 7.0.0 but it looks more correct, and the basic error (result from only the first shape) is resolved.